Cryotherapy is a useful treatment modality for many types of medical procedures. In some cases, it is desirable to administer cryotherapy from within a patient's body, such as from within a body lumen. Internal administration of cryotherapy can be advantageous, for example, in at least some neuromodulation procedures. These procedures can include percutaneously introducing a cryotherapeutic element into a patient and then advancing a catheter shaft carrying the cryotherapeutic element along an intravascular path to a suitable treatment location. Once positioned at the treatment location, the cryotherapeutic element can be cooled to modulate nearby nerves. The cooling caused by the cryotherapeutic element, for example, can reduce undesirable local or systemic sympathetic neural activity and thereby achieve various therapeutic benefits.
Cryotherapy may have certain advantages relative to other modalities for executing some types of treatments. For example, in the case of neuromodulation, adhesion associated with freezing may assist in achieving uniform and stable contact between a cryotherapeutic element and surrounding tissue for a sustained period of time while neuromodulation occurs. As another example, cryotherapy may be relatively unlikely to cause stenosis at an intravascular treatment location. As yet another example, cryotherapy may tend to provide a beneficial analgesic effect and, therefore, may reduce the need for analgesic medication. Technical challenges associated with cryotherapy, however, can make these and other advantages difficult to realize. Accordingly, innovation in this field to address such challenges has significant potential to make cryotherapy a more effective, efficient, and widely used tool for improving the health of patients.